我的數據庫中有3個表,分別命名爲items
,manufacturers
和items_manufacturers
。 manufacturers
擁有包括:與items_manufacturers
SQL使用內部連接加入三個表
我items
表中的許多關係
+---------------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+---------------+--------------+------+-----+---------+----------------+
| id | bigint(20) | NO | PRI | NULL | auto_increment |
| code | varchar(25) | NO | MUL | NULL | |
| item_category | varchar(100) | NO | | NULL | |
| item_desc | varchar(500) | NO | | NULL | |
| reorder_point | int(11) | NO | | NULL | |
| unit | varchar(45) | NO | | NULL | |
+---------------+--------------+------+-----+---------+----------------+
我manufacturers
表
+------------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+------------+--------------+------+-----+---------+----------------+
| id | bigint(20) | NO | PRI | NULL | auto_increment |
| code | varchar(25) | NO | | NULL | |
| name | varchar(250) | NO | | NULL | |
| address | varchar(750) | NO | | NULL | |
| contact_no | varchar(50) | NO | | NULL | |
+------------+--------------+------+-----+---------+----------------+
我items_manufacturers
表
+-----------------+---------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------------+---------------+------+-----+---------+----------------+
| id | bigint(20) | NO | PRI | NULL | auto_increment |
| item_id | bigint(20) | NO | MUL | NULL | |
| manufacturer_id | bigint(20) | NO | MUL | NULL | |
| unit_cost | decimal(20,2) | NO | | NULL | |
| vendor_id | bigint(20) | NO | | NULL | |
+-----------------+---------------+------+-----+---------+----------------+
在我的結果表餘萬t items_id
,items_desc
,name
製造商從manufacturers
表和manufacturer_id
。我有的關係是
items.id=items_manufacturers.item_id and
manufacturers.id=items_manufacturers.manufacturer_id.
我嘗試使用三個表的內部聯接,但不工作。 查詢我試圖
select
items_manufacturers.id,
items.item_desc,
item_manufacturers.manufacturer_id,
manufacturer.name
from items_manufacturers
INNER JOIN items ON items_manufacturers.item_id=items.id
INNER JOIN manufacturers ON items_manufacturers.manufacturer_id=manufacturers.id
有人好心幫助我,我從很久
查詢看起來OK。當你說它不起作用時,你是什麼意思?你能解釋爲什麼結果不符合你的期望嗎? –
正如吉姆上面所說,我想知道爲什麼不工作?你有什麼錯誤嗎?你有沒有得到任何結果?據我所知,你的查詢似乎對我很好。 – Christos
這讓我好奇,因爲你似乎有一個工作查詢,但你說你卡長時間.. –